In the course of various qualitative analysis procedures, the
fo...

Question

In the course of various qualitative analysis procedures, the 
following mixtures are encountered: (a) Zn2 + and Cd2 + . Suggest how each mixture might be separated.

Accepted Answer

Hey everyone today, we're being asked to identify which rages can be used to separate. And too many three plus and cobalt two plus in a solution. Now, before doing anything, we need to recall that even though it isn't explicitly stated in the question, we're dealing with cad ions that are dissolved in aqueous solutions, dissolved in aqueous solutions. And this is because only then will our soluble itty rules actually have any bearing on what re agents that we're using. So now we can go ahead and start looking at our agents. We'll start with the first one which is six smaller hydrochloric acid and we can actually rule this out. And this is because chlorine when reacting with um antimony or cobalt will form, let's write this out in green. It'll form either SB cl three or cobalt cl two. But because the chlorine isn't bonded to a silver lead or mercury, these will both be soluble salts. So they won't really be able to separate from one another. They'll both be soluble in solution, which means since one hasn't precipitated, we can't really separate them so we can rule the answer choice A off for answer choice B. However, and let's erase these for answer choice B. We're going to end up with two separate um products we're going to have S. P two, S three, Antoninus tri sulfide or C. O. S cobalt sulfide. Now the important thing to note here is that we're not just dealing with hydrogen sulfide is one of the reactant, we're also dealing with two molar hcl were in an acidic environment and due to the acidity due to our ability rules the Antoninus tri sulfide will actually end up being insoluble. It'll be insoluble in these acidic environments, but the cobalt sulfide will still be soluble At the Ph of eight, which means this indeed, is our answer choice. The sp three plus will end up precipitating out while the cobalt stays dissolved in solution, which means it is the easiest way for us to separate the two Catalans. Using the re agents hydrogen sulfide, two molar hydrochloric acid. I hope this helps. And I look forward to seeing you all in the next one.

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